1.Field of the Invention
The present invention relates to a package container forming flap apparatus in a filling and packaging apparatus for manufacturing package containers each having a rectangular shape in cross section and filled with a fluid content such as juice, etc. and a method of forming the package container using the same.
2. Prior Art
There is known a conventional filling and packaging apparatus comprising a rewinder for supporting a packaging material web in a rolled state, a winding apparatus for winding the web in order from the rewinder, a tube-forming apparatus for forming the wound web in a tubular shape after sterilizing it, a liquid supply pipe for filling a fluid content in the tubular shaped packaging material web, and a container-forming apparatus for laterally sealing the tubular web filled with the fluid content and cutting a sealed part of the tubular web to continuously form pillow-like containers each having a rectangular shape in cross section while downwardly supplying the tubular web by the length corresponding to one container, and a container shaping apparatus for bending each end part of the pillow-like containers to shape each pillow-like container in a parallelepiped container to be finally obtained (as disclosed in JP-A 58-193206 and JP-A 61-93010).
As a package container forming flap of a container forming apparatus in such a filling and packaging apparatus, it is known that a tubular body is formed in a rectangular shape by the movement of two pistons from two directions crossing at right angles with opposing plates after the tubular body is supplied between the opposing plates (U.K. Patent Number 1,012,867), or a tubular packaging material is formed in a box-shape from the bottom to the top thereof using longitudinal forming flap members 4 which turn longitudinally about axes 3 disposed in a direction parallel with a direction crossing at right angles with a longitudinal direction of the tubular packaging material 2 over the lateral seal bars 1 as shown in FIG. 1 when forming a liquid filling and packaging container by filling a content in a tubular packaging material web, laterally sealing and cutting this web after the plate-shaped packaging material web is formed in the tubular packaging material web (JP-A 58-193206) or a protrusion and a recess are provided on opposing surfaces of the forming flap members for forming the tube in a rectangular shape (JP-A 5-32208).
However, there are following drawbacks in these forming flaps.
In the forming flap as disclosed in U.K. Patent Number 1,012,867, the structure of the forming flap is made large and complex since the tubular body is formed in a rectangular shape by the plates and the pistons.
In the forming flap disclosed in JP-A 58-193206, since the forming flap members are turned in the longitudinal direction when the tubular shape is changed to a box-shape by the forming flap members, a soft packaging material such as paper is nipped between contact surfaces of the opposing forming flap members in the longitudinal direction, so that a fold or wrinkle 5 is produced at the side surfaces of the tubular packaging material 2 as shown in FIG. 2, which causes a problem that an external appearance is deteriorated, the tubular packaging material 2 does not have an intended size of the container, and proper inner capacity of the container is not obtained, thereby impairing a product value.
Further, since the forming flap members are turned approach to each other in a longitudinal direction thereof to form the tubular packaging material from a circular shape in cross section to a rectangular shape in cross section, the container has an inverted trapezoidal shape in longitudinal cross section because of the adjustment of the inner capacity of the container, which causes a problem of inconvenience of packaging or carriage of the container. Still further, the surface of the packaging material web is liable to be damaged because the inner surfaces of the forming flap members and the web slide when forming the tubular packaging material web.
In the forming flap as disclosed in JP-A 5-32208, the protrusion and the recess are defined on the contacting surfaces of the opposing forming flap members to improve the drawback of JP-A 58-193206 that the longitudinal forming flap members nip the packaging material web in the longitudinal direction thereof, whereby the nipping of the packaging material web can be prevented to some extent but it is not completely prevented. Further, the problem of inconvenience of the shape of the container that the container has the inverted trapezoidal shape in longitudinal cross section has not been solved so far.